New Zealand is offering diplomatic and political support for military action to enforce the United Nations ceasefire in Libya, but could not practically offer military support, Prime Minister John Key says.

The military action, by the United States and European nations, was sanctioned after Libyan leader Muammar Gaddafi did not adhere to the ceasefire and ignored the message from the Paris Summit that there would be intervention.

Key said New Zealand was too far away to offer military support and Nato had more than enough resources.

"It's quite clear that Gaddafi has been undertaking violence against his people, it's abhorrent, we want to see that end, and we do want to see a smooth and peaceful transition to a new leader." The majority of the Libyan people wanted the same, he told TVNZ's Breakfast.

Gaddafi would not go easily, but would eventually be replaced as Libyan leader, Key said.

There was also concern about the situation in Bahrain and Yemen which were being closely monitored.

"For a period of time, a number of the security council members had petitioned very hard for sanctions to be put on Libya, and obviously for there to be a no fly zone and eventually that agreement was reached."

Foreign Affairs Minister Murray McCully said yesterday that four New Zealanders had chosen to remain in Libya. Since violence broke out last month, 29 New Zealanders had left.

Labour leader Phil Goff said he supported the military action because it was sanctioned by the UN.

"To stop the slaughter of civilians and innocent people I'm firmly behind intervention to prevent that happening. The wider question is how to resolve the situation within Libya itself rather than simply leaving it at an impasse."